Ventilating screen



J. HARRIS VENTILATINE SCREEN Dec. 31, 1929.

Filed Nov. 4, 1927 Patented Dec. 31, 1929 PATET FECE JOSEPH HARRIS, F WHEATON, ILLINOIS VENTILATING- SCREEN Application filed November 4, 1927. Serial No. 231,092.

This invention relates to improvements in ventilating screens and more particularly ventilating screens for moving vehicles such as railway passenger carsand the like.

As is well known, the travelling public is subject tomuch annoyance and discomfort when travelling in warm weather in railway passengercars, due to the fact that its is necessary to obtain ventilation for cooling purposes but which, heretofore, has been attended with the intake of much dust and dirt to the interior of the car through the usual window screens. I am aware that many efforts have heretofore been made to 1 provide means to prevent the intake of dust and dirt through window openings of moving passenger cars but, so far as I am aware, none of the same has ever gone into practical use due either to their impractical nature, ex-

' pense or disadvantages in operating or maintaining the same.

One object of my invention isto provlde a ventilating screen which is particularly adaptable for use on railway passenger cars such as the modern Pullmans, which screen will permit of the desired circulation of air; which will 'minimize' and practically elimihate the admission of any dust or dirt particles through the screen while the car is in motion; which will be of relatively inexpensive manufacture; and which may be utilized in modern Pullman cars without modification of the structures now. commonly employed therein. l ()ther objects of the invention will more clearly appear from the description: and

claim hereinafter following.

In the drawing forming a part of this specification, Figure 1 is an inside View of a sec tion of a modern sleeping car or so-called Pullman and showing my improvements in connection therewith. Figure 2 is an en larged horizontal, sectional view corresponding approximately to the section line 2-2 of Figure 1. h

In the modern Pullman car to which my improvement is more especially adapted, it is common to arrange the windows along the side walls of the car in pairs, one pair for each section, the two windows of the pair being of the pair.

separated by a post. Further, it is customary, to employ at each window opening two wlndow sashes,

an outer and an inner sash, both of which are vertically slidable so that both or either may be opened when desired. It is also customary in the modern Pullman to employ a sash screen disposed intermediate each of the two window sashes for each window, which moved up and down sash screen may also be and brought mtouse or disposed in an inoperative position dependent upon the dlrectlon 1n whlch the tram 1s moving. Likewise, it is customary to employ a baffle on the outside of the post intermediate the two windows of each pair, which bafiie is utilized in connection with the screens to reduce the amount of dust entering the screen.

In carrying out my invention, I have found it unnecessary to depart in any way from the general arrangement andmake use of the 12 being the usual for a section of the rated by the usual window post 13. In

arrangement of a pair Pullman car and sepaeach window opening, there are two slidable window sashes l4 and 15, of which only those for the window opening 11 are illustrated, the same being shown closed. The windows 14 and 15 slidein vertical respectiveh this guideways 16 and 17 being true of both windows L As further customary, there is a centrally disposed set of vertical guides or grooves 18-18 for each window in which is shdably mounted the screen sash, one of which is indicated at 19 in the operative posi tion in the window vertically extending opening 12. The usual baffle 20 is indicated in the drawings, the same being either permanently or detachably but rigidly applied to the center of the outside face of the post 13 and being of approximately the same vertical height as the opening dows are open.

Referring to the the left, it is the usu provided when the windrawings, when the car or Pullman is moving in a direction toward al practice to elevate the screen in the forwarding window opening 11 and maintain the windows 14 and 15 in closed position and, at the same time, to elevate or fully open the corresponding windows in the rear window opening 12 while maintaining the screen sash in lowered or operative position, as indicated in the drawing. From observation, I have found that, notwithstanding that the screens now commonly employed are of comparatively fine mesh throughout, large quantities of dust and dirt are driven to the interior of the car through the screen left in operative position and more particularly in the rear portion thereof, considered with reference to the direction of travel of the car. In other words, the dust and dirt is driven in at points which are the most objectionable to a passenger sitting in the seat adjacent the window and facing forwardly with the result that much discomfort and annoyance is produced. Further, observation has shown that this result is due to anarea of increased air pressure produced on approximately the rearhalf of the screen, that is, the half farthest away from the baffie and rearwardly thereof considered with reference to the direction of movement. While there is thus created an area of increased air pressure accelerating the driving in of dust and dirt particles, there is at the same time created an area or zone of decreased air pressure on approximately the forward half of the screen when used in operative position. These zones or areas of increased and decreased air pressure are produced by the air currents created by the baflle 20 while the car is in motion, as will be understood, there being a partial vacuum created behind the bafile for a short distance and thereafter a small neutral or normal air pressure areaand rearwardly of the latter an increased air pressure area.

With my improvements, I utilize the effects of increased and decreased air pressures thus created to eliminate or minimize the inward passage of dust and dirt particles while permitting the exhausting of air for ventilating purposes. To this end, each improved screen 19 will have the approximately rear half 19 of an extremely fine mesh and the forward or front half 19 thereof of a relatively coarser mesh. As is well known to those skilled in the art, the finer the mesh of a screen, the greater the interference to the passage of solid particles therethrough and the rear portion 19, that is, the portion farthest from the baffle and to the rear side thereof with reference to the motion of the vehicle will preferably be made of a mesh twice as fine as that now customarily used. This finer mesh will not prevent the passage of air therethrough, but will knock down or stop practically all particles of dust or dirt on the outside of the screen. With reference to the forward half or portion of the screen 19", the same may be made of the present commonly used mesh or considerably larger mesh in order to facilitate the exhausting of air therethrough since experience demonstrates that there is practically no tendency whatsoever to drive any dust particles inwardly through the forward portion 19 of the screen while the car is in motion.

One effective way of providing a screen having the special characteristics indicated,

is to double the number of warp wires in thescreen for half of its width when the same is being woven. Other ways of accomplishing the same effective, extremely fine mesh over the desired area will readily suggest themselves to those skilled in the art, one such method being to provide an additional screen section which will overlie the rear half portion of the screen.

From the preceding description, considered in connection with the drawing, it will be observed that when my improvements are applied to the modern sleeping or Pullman car, no changes are required either in the general arrangement and construction of the parts or the common mode of using the windows, sash screens and bafiles of standardized forms. It will further be observed that the attendants in charge of the cars will require no special instructions, but will proceed as now custcmary and, by placing the improved screens in their proper positions in the first place with reference to the baffle, they will always thereafter be in position to automatically perform their function without any special attention or care from anyone. Further, while the increasing of the mesh over a portion of the improved screen will tend somewhat to decrease the factor of visibility, it occurs in such a portion as not to seriously interfere with passengers looking out through the screen and observing therethrough since the passenger will ordinarily look in a direction at an angle forwardly as well as outwardly.

Although 'I have herein shown and described what I now consider the preferred manner of carrying out my invention, the

same is merely illustrative and I contemplate all changes and modifications that come within the scope of the claim appended hereto.

I claim In a ventilating screen for movable vehicles having an opening in a wall thereof and provided with a baflle on the outside of said wall disposed adjacent to and at the forward side of the opening with reference to the direction of movement of the vehicle whereby an area of decreased air pressure immediately rearwardly of the battle and an area of increased air pressure further rearwardly of the battle is created when the vehicle is in motion, said ventilating screen having one portion thereof formed with an effective relatively very fine mesh adapted to be disposed in said area of increased pressure to minimize inward passage of solid particles therethrough and having another portion 7 thereof of an effective relatively coarser mesh adapted to be disposed in said area of decreased pressure to readily permit air being exhausted outwardly therethrough.

In Witness that I claim the foregoing I have hereunto subscribed my name this 31st day of October, 1927.

JOSEPH HARRIS. 

